Wheel chocking device and method for using the same

ABSTRACT

A method of securing a vehicle at a desired location using a wheel chocking device ( 30 ) having a chock ( 38 ) movable between a lowered position and a raised position. The method comprises the steps of positioning the vehicle at the desired location with the chock ( 38 ) in the lowered position, raising the chock to the raised position, moving the raised chock toward a wheel of the vehicle, sensing the presence of an obstruction on the vehicle, lowering the raised chock to an intermediate position to allow the chock to pass under the obstruction, and contacting the chock with the wheel. The wheel chocking device ( 30 ) includes a drive mechanism ( 40 ) that is positioned underneath the chock so that the vehicle actually drives over the drive mechanism. The drive mechanism is simplified with the use of a drive screw ( 152 ) and a partial drive nut ( 148, 154 ) that facilitates the use of support members ( 156 ) for supporting the drive screw at spaced locations along the length of the drive screw. A multi-link chock facilitates use of the device on wheels of varying sizes.

This application is a 371 of PCT/US97/11081 filed Jun. 25, 1997 and alsoclaims benefit of Provisional No. 60/020,686 filed Jun. 27, 1996.

FIELD OF THE INVENTION

The present invention generally relates to the field of vehiclerestraining devices that prevent movement of a vehicle away from adesired location. More specifically, the present invention relates topowered wheel chocking devices.

BACKGROUND OF THE INVENTION

Powered wheel chocking devices have been developed to allow a vehicle(e.g., a straight truck, a trailer with or without a tractor, etc.) tobe secured at a desired location (e.g., a loading dock) so that loading,unloading or other operations can be performed without risk that thevehicle will unexpectedly move away. Such wheel chocking devicestypically include a chock that can be selectively moved by a drivemechanism between a chocked position and an unchocked position. Thesedevices are commonly provided with visual and audible signals thatindicate when the chock is in the chocked position and when the chock isin a unchecked position.

One type of powered wheel chocking device has been designed by MichelRoux, and is disclosed in European Patent Publication No. 537,075. TheRoux device includes a chock that is movable between an uncheckedlowered position and chocked raised position. The Roux device isdesigned to maintain the chock in a lowered position until the chock hasbeen moved longitudinally into contact with the vehicle wheel. Aftercontact with the vehicle wheel, further movement of the drive mechanismcauses the chock to pivot to the raised position to secure the vehiclewheel.

A similar device is disclosed in U.S. Pat. No. 5,375,965 to Springer etal. The Springer device also includes a chock that is movable betweenlowered and raised positions, and the chock is designed to be movedlongitudinally into contact with the vehicle wheel while the chock is inthe lowered position. After contact with the wheel, the drive mechanismwill continue to drive a portion of the chock until the chock moves tothe raised position.

SUMMARY OF THE INVENTION

One problem with the above noted powered wheel chocking devices is thatthe chock can prematurely move to the raised position before the chockis positioned in contact with the vehicle wheel. This can be caused byan impediment (e.g., ice, debris, damage or other discontinuity) in thepath of the chock. Such an impediment can restrict movement of the chockto such a degree that the device acts as if the vehicle wheel has beenengaged, when in fact it has not been engaged. The result is that thechock can prematurely move to the raised position. After the chock israised, the drive mechanism can overcome the impediment and continuemoving the raised chock toward the vehicle wheel. If the vehicleincludes depending obstructions (e.g., tool boxes, spare tires, etc.)hanging down from the vehicle in the chock's path, the raised chockcould engage the obstruction and give a false indication that thevehicle wheel has been properly engaged.

Another problem with some of the prior art devices is that the drivemechanisms are unnecessarily complex, requiring sliding support blocksand collapsing chock wheels. Some of these devices also position thedrive mechanism offset from the wheel path, thereby requiring the use oftwo chocks and a centered drive mechanism to compensate for themisaligned forces involved in securing the vehicle.

The present invention alleviates the above noted problem by providing awheel chocking device that is designed to deflect around anyobstructions that could be depending from a vehicle in the chock's path.In this regard, the invention is embodied in a method of securing avehicle at a desired location- using a wheel chocking device having achock movable between a lowered position and a raised position. Themethod comprises the steps of positioning the vehicle at the desiredlocation with the chock in the lowered position, raising the chock tothe raised position, moving the raised chock toward a wheel of thevehicle, sensing the presence of an obstruction on the vehicle, loweringthe raised chock to an intermediate position to allow the chock to passunder the obstruction, and contacting the chock with the wheel.

The present invention also provides a wheel chocking device having adrive mechanism that is positioned underneath the chock so that thevehicle actually drives over the drive mechanism. The drive mechanism ofthe present invention is simplified with the use of a drive screw and apartial drive nut that facilitates the use of support members forsupporting the drive screw at spaced locations along the length of thedrive screw. A multi-link chock facilitates use of the device on wheelsof varying sizes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a wheel chocking device embodying thepresent invention and positioned at a loading dock.

FIG. 2 is a partial top view of the wheel chocking device of FIG. 1.

FIG. 3 a section view taken along line 3—3 in FIG. 2.

FIG. 4 is a schematic section view taken along line 4—4 in FIG. 2 withthe chock in a lowered position.

FIG. 5 is the section view of FIG. 4 with the chock in a raisedposition.

FIG. 6 is the section view of FIG. 4 with the chock in an intermediateposition deflecting around an obstruction.

FIG. 7 is the section view of FIG. 4 with the chock in a raised andsupported position at a vehicle wheel.

FIG. 8 is the section view of FIG. 4 illustrating the action of thechock when the vehicle wheel is driven.

FIG. 9 is a perspective view of the interior components of the chockwhen the chock is in the lowered position.

FIG. 10 is the perspective view of FIG. 9 with the chock in a raisedposition.

FIG. 11 is the perspective view of FIG. 9 with the chock in a raised andsupported position.

FIG. 12 is a section view taken along line 12—12 in FIG. 2.

FIG. 13 is a section view taken along line 13—13 in FIG. 2.

FIG. 14 is a section view taken along line 14—14 in FIG. 2.

FIG. 15 is a section view taken along line 15—15 in FIG. 2.

FIG. 16 is a side section view taken along line 16—16 in FIG. 1.

FIG. 17 is a top section view taken along line 17—17 in FIG. 16.

DETAILED DESCRIPTION

The illustrated wheel chocking device 30 generally includes a base frame32 adapted to be secured to an underlying surface 34, a cover plate 36covering the base frame 32, a chock 38 positioned over the cover plate36 and adapted to slide relative to the base frame 32, and a drivemechanism 40 positioned substantially within the base frame 32 and underthe cover plate 36. The wheel chocking device 30 is specificallydesigned to be positioned adjacent to a loading dock 42 so that avehicle that is backed against the loading dock 42 can be secured inposition adjacent to the loading dock 42. As used herein, the rearwarddirection denotes movement toward the loading dock 42 as resented by thearrow 46, and the frontward direction is opposite to the rearwarddirection as represented by the arrow 48.

Referring to FIGS. 1, 2 and 12, the base frame 32 includes a base plate50 that is designed to be secured to the surface 34 by a series offasteners 52. For example, the illustrated base plate 50 is secured to aconcrete or asphalt driveway in front of the loading dock 42. Referringspecifically to FIG. 12, inner side walls 54 are secured to the baseplate 50 and define a recess 56 therebetween for housing a portion ofthe drive mechanism 40, as described below in more detail. Outer sidewalls in the form of guide members 58 and support members 60 define sideslots 62 for guiding the drive mechanism 40, as described below in moredetail. The inner side walls 54 and guide members 58 cooperativelyprovide a non-securing support for the cover plate 36. That is, thecover plate 36 rests upon but is not secured to the inner side walls 54and guide members 58. Side angles 64 are secured to the longitudinaledges of the base plate 50 to protect the wheel chocking device 30 frompotential damage from snow plows. The side angles 64 could be madedetachable (e.g., by attaching with bolts) from the base plate 50. Thebase plate 50 is further provided with stop blocks 66 (FIGS. 2 and 15)that stop movement of the drive mechanism 40 in the frontward direction,as described below in more detail.

The cover plate 36 extends along substantially the entire length of thebase frame 32 to provide a protective cover for the drive mechanism 40.The cover plate 36 allows a vehicle 44 to drive on top of the wheelchocking device 30 without damaging any of the components of the drivemechanism 40. The cover plate 36 is secured to the base frame 32 only atits ends, and thus the middle portion of the cover plate 36 is allowedto move vertically away from the base frame 32 or “float” to allowportions of the drive mechanism 40 to pass between the base frame 32 andthe cover plate 36. This allows the drive mechanism 40 to beinterconnected with the chock 38.

Referring to FIGS. 2-8, the chock 38 generally includes a rear portion68 adapted to engage a vehicle wheel 108, and a front portion 70 that ismovably interconnected with and provides support to the rear portion 68.Referring specifically to FIGS. 2 and 3, the rear portion 68 comprises aseries of three links: a lower link 72, a middle link 74 and an upperlink 76. The lower link 72 includes a lower plate 78 and a lower sidemember 80 secured near each side of the lower plate 78 (see FIGS. 3 and15). The middle link 74 includes a middle plate 82 and a middle sidemember 84 secured near each side of the middle plate 82 (FIG. 3). Themiddle side members 84 are pivotally connected to the lower side members80. The upper link 76 comprises an upper plate 86 and an upper sidemember 88 secured near each side of the upper plate 86. The upper sidemembers 88 are pivotally secured to the middle side members 84. Uppertube members 90 (FIGS. 2 and 4) are secured to the upper plate 86 toprovide a location for securing the upper link 76 to the front portion70 of the chock 38.

The front portion 70 of the chock 38 includes a single large link 91comprising a large plate 92 and a large side member 94 secured near eachside of the large plate 92 (FIG. 3). A front tube member 96 (FIG. 2) issecured to the large plate 92 in alignment with the upper tube members90. The front tube member 96 and upper tube members 90 are designed toreceive a pin member 98 for pivotally securing the large link 91 withthe upper link 76.

A support link 100 is pivotally connected to the pin member 98 (FIGS. 2and 4-8). The support link 100 includes a support plate 102 and twohinge members 104 secured to each side of the support plate 102. Thehinge members 104 are positioned between the upper tube members 90 andthe front tube member 96 and are designed to receive the pin member 98so that the support link 100 is pivotally attached to the pin member 98.A cross member 106 is secured to the other end of the support plate 102to provided a more stable footing for the support link 100 when itengages the cover plate 36, as described below in more detail. The crossmember 106 also provides an attachment point for two link members 107.In the illustrated embodiment, the link member 107 are made from aflexible material, such as chain, and their function is described belowin more detail.

The above-described chock 38 is designed to slide longitudinally (i.e.,in the frontward and rearward directions) relative to the base frame 32and cover plate 36. Such sliding motion allows the chock 38 to be movedinto contact with a vehicle wheel 108 positioned on the cover plate 36.More specifically, the chock 38 can be moved from a stored position(FIGS. 3 and 4) to a raised and unsupported position (FIG. 5). When thechock is in the unsupported position, the support link 100 does notsupport the chock 38. In this unsupported position, the chock 38 isdesigned to have the ability to deflect around an obstruction 109hanging down from the vehicle 44 (FIG. 6). Once the raised chock 38 isbrought into contact with the vehicle wheel 108, the support link 100will move to a supporting position in a manner described below in moredetail. In the supporting position, the support link 100 will preventthe chock 38 from deflecting downward in the event that the vehicleattempts to drive away from the loading dock (FIG. 8).

The chock 38 is moved and raised by the drive mechanism 40. The drivemechanism 40 is best shown in FIGS. 9-15, and includes, inter alia, afront slider 110, a rear slider 112, and a drive member 114.

The front slider 110 comprises a front plate 116 slidably positionedbetween the base frame 32 and the cover plate 36 (FIGS. 9 and 13). Afront block 118 is secured to each side edge of the front plate 116.Each front block 118 includes a front slot 120 and a front hole 122 forfacilitating pivotal engagement with the large side members 94 of thelink (see FIGS. 2, 3 and 13). The front slider 110 further includes twofront tubes 124 secured to the bottom surface of the front plate 116,and a front spring bracket 126 secured to each front tube 124. Becauseof the pivotal engagement between the front slider 110 and the largelink 91, it can be seen that movement of the front slider 110 willresult in movement of the front end of the large link 91.

The rear slider 112 includes a rear plate 128 slidably positionedbetween the base frame 32 and the cover plate 36 (FIGS. 9 and 15). Arear block 130 is secured to each side edge of the rear plate 128. Eachrear block 130 includes a rear slot 132 and a rear hole 134 forfacilitating pivotal engagement with the lower side members 80 of thelower link. Each rear block 130 is provided with a bar member 136positioned within the side slots 62 formed by the guide members 58 ofthe base frame 32 (FIGS. 2 and 15). The bar members 136 provide guidanceto the rear slider 112 and prevent the rear slider 112 from movingupwardly away from the base frame 32. The bar members 136 furtherprovide a means for stopping movement of the rear slider 112 in thefrontward direction. More specifically, the bar members 136 will contactthe stop blocks 66 of the base frame 32 to stop the rear slider 112 inthe stored position (see FIG. 2). The rear slider 112 further includestwo spring tubes 138 secured to the bottom surface 34 of the rear plate128, and a rear spring bracket 140 secured to each spring tube.

The front slider 110 and rear slider 112 are interconnected by two coilsprings 142 secured on one end to the front spring brackets 126 and onthe other end to the rear spring brackets 140 (FIG. 9). The coil springs142 provide a biasing force tending to pull the front slider 110 andrear slider 112 toward each other. Such movement of the front slider 110and rear slider 112 toward each other will result in the chock 38 movingto the raised position. Thus, the chock 38 is biased to the raisedposition.

The drive member 114 is operatively positioned between the front slider110 and the rear slider 112. The drive member 114 is designed to drivethe rear slider 112 when the chock 38 is being moved in the rearwarddirection, and is designed to drive the front slider 110 when the chock38 is being moved in the frontward direction. The drive member 114comprises a drive plate 146 slidably positioned between the base frame32 and the cover plate 36, and a drive block 148 secured to the bottomsurface of the drive plate 146 (FIGS. 9 and 14). The drive block 148includes internal threads 150 for threadedly engaging a screw member152. The drive block 148 includes an open portion 154 such that theinternal threads 150 do not engage the entire outer circumference of thescrew member 152.

The open portion 154 of the drive block 148 allows an arcuate segment ofthe screw member 152 to be supported by a series of lower screw supports156 spaced along the longitudinal length of the screw member 152. In apreferred embodiment, the longitudinal position of the lower screwsupports 156 is limited by a plurality of spaced weld beads 155 (FIGS.12-15) between the base frame 32 and the side walls 54. Upper screwsupports 157 are secured to each of the front plate 116 and the rearplate 128 (FIGS. 9-15). The upper and lower screw supports 156,157 arepreferably made from a low friction material (e.g., brass, plastic,etc.) to provide low friction engagement between the screw member 152and the lower screw supports 156. In the illustrated embodiment, theupper and lower screw supports are made from a polymer material, such asultra high molecular weight polyethylene.

The drive member 114 further includes two drive tubes 158 (FIGS. 10 and14) secured to the bottom surface of the drive plate 146. The drivetubes 158 are positioned in alignment with the front tubes 124 on thefront slider 110. The drive tubes 158 and front tubes 124 slidablyreceive a rod 160 having collars 162 that prevent the rod 160 fromsliding out of the tubes. A gas spring 164 is operatively positionedbetween each rod 160 and the corresponding spring tube 138 of the rearslider 112. Each gas spring 164 includes a cylinder 166 (FIG. 9)slidably positioned within the corresponding spring tube, and a pistonrod 168 secured to the corresponding rod 160 by a coupling 170 and setscrew 171. In the illustrated embodiment, the piston rod 168 is biasedaway from the cylinder 166 at a force of about 100 lbs. The link members107 are secured to opposing sides of the drive member 114, and aredesigned to control the position of the support link 100 in relation tothe position of the drive member 114.

The above-described components of the drive mechanism 40 operate in thefollowing manner to provide movement to the chock 38. In the storedposition, the drive member 114 pushes the front slider 110 all the wayto the front end of the base frame 32 (FIGS. 4 and 9). In this position,the rear slider 112 is held in spaced relation to the front slider 110by the stop blocks 66 interacting with the bar members 136 (FIG. 2). Inthe stored position, the coil springs 142 are stretched, and thecylinder 166 of the gas spring 164 is partially pulled out of the springtubes 138. The support link 100 is held in a non-supporting position bythe link members 107.

Movement of the device is initiated by rotating the screw member 152,which results in movement of the drive member 114 in the rearwarddirection. Due to the biasing force of the coil springs 142, the frontslider 110 will follow the rearward movement of the drive member 114,thereby resulting in raising of the chock to a raised position (FIGS. 5and 10). At this point, the drive member 114 contacts the couplings 170,and the cylinders 166 are bottomed out within the spring tubes 138.Further movement of the drive member 114 therefore results in driving ofthe rear slider 112 in the rearward direction. The support link 100 isheld in a non-supporting position by the link members 107.

If the raised chock encounters an obstruction 109 while movingrearwardly toward the wheel, the chock will deflect around theobstruction 109 and will subsequently return to the raised positionafter the obstruction 109 has been passed (FIG. 6). Such downwarddeflection of the chock is facilitated by the compliant biasing of thefront slider 110 toward the rear slider 112, and further by the factthat the rear slider 112 is being driven. More specifically, if anobstruction 109 is encountered, the rear slider 112 will continue to bedriven rearwardly, and the front slider 110 is allowed to slideforwardly, if necessary, to allow the chock to deflect downwardly to anintermediate position. Because the support link 100 is in anon-supporting position, the support link 100 does not interfere withthe downward deflection of the chock. Furthermore, the flexible natureof the illustrated link members 107 allows the drive member 114 to moverelative to the support link 100. Rather than have the wheel chockcontact the obstruction, the wheel chock could be provided with aproximity sensor that senses the presence of an obstruction. If anobstruction is sensed, then the chock could be automatically lowered toa height lower than the obstruction (e.g., using a powered loweringmeans, such as an electric motor) until the obstruction is passed.

Once the vehicle wheel 108 has been engaged by the chock, the rearslider 112 will stop, but the drive member 114 will continue rearwardmovement until the collars 162 of the rods 160 engage the front tubes138 and couplings 170 engage the spring tubes 138 (FIGS. 7 and 11). Suchmovement of the drive member 114 results in the support link 100 movingto the supporting position, thereby placing the chock 38 in the raisedand supported position.

Movement of the chock 38 back to the stored position is accomplished insubstantially the reverse order. It is noted, however, that movement ofthe chock 38 in the frontward direction is accomplished by driving thefront slider 110. In this manner, the chock 38 will be allowed todeflect downwardly to an intermediate position to avoid any obstructionsthat may be encountered when moving the chock 38 back to the storedposition.

The illustrated screw member 152 is driven by a power mechanism in theform of an electric motor 172 interconnected with the screw member 152by a drive shaft 174 (FIGS. 16 and 17). The drive shaft 174 includesflexible couplings 176 for accommodating misalignment of the motor shaftwith the screw member 152 (only one end is shown). The screw member 152is slidably mounted within screw bushings 178 positioned on either endof the screw member 152. That is, the screw member 152 is supported by,but is not axially restrained by the screw bushings 178. Each end of thescrew member 152 is provided with a screw collar 180 secured to thescrew member 152, and a biasing spring 182 positioned between the screwbushing and the screw collar 180. In this manner, the screw member 152is biased to a neutral position (FIG. 17) relative to the screw bushings178.

A sensing mechanism is provided for sensing the axial position of thescrew member 152. In the illustrated embodiment, the sensing mechanismincludes a first sensor 184 positioned in alignment with the screwcollar 180 when the screw member 152 is in a neutral position, and asecond sensor 186 positioned to detect movement of the screw member 152in the rearward direction. When the screw member 152 is being used tomove the chock in either direction, the screw member 152 is positionedin the neutral position. When the chock has engaged a vehicle wheel, thescrew member 152 will move frontwardly due to the resistance encounteredby the drive member 114. Such frontward movement of the screw member 152will be detected by the first sensor 184. Conversely, when the chock isin the stored position, the screw member 152 will move rearwardly due tothe resistance encountered by the bar members 136 on the stop blocks 66.Such rearward movement of the screw member 152 will be detected by thesecond sensor 186. Information regarding the axial position of the screwmember 152 can be provided to a control mechanism 188 (shownschematically in FIG. 17) and used to selectively disengage the powerdrive mechanism. More specifically, when the screw member 152 movesrearwardly, it is an indication that the stored position has beenreached and the motor can be deactivated. Conversely, frontward movementof the screw member 152 indicates that a wheel has been engaged and themotor can be deactivated.

Alternatively, the power mechanism can be provided with atorque-limiting device, such as a torque or current sensor, todeactivate the power mechanism. As another alternative, a proximitysensor can be used to sense when the drive member 114 is in the storedposition (FIGS. 3, 4 and 9). The use of a proximity sensor isadvantageous in that it is a positional sensor that directly measuresthe position of the drive member 114, as opposed to a conditional sensorthat measures a certain condition of the chock and infers the positionof the chock.

The above-noted mechanisms for sensing the position of the wheel chockcan be used to provide signals to a communication system. For example,the loading dock can be provided with a dock lighting system forcommunicating with the dock workers and a driver lighting system forcommunicating with the driver of the vehicle. Each lighting system caninclude a red light and a green light. When the chock is in the storedposition, the driver lighting system will show a green light, indicatingthat the driver can enter or exit the loading dock, and the docklighting system will show a red light, indicating that no loading orunloading operations should be performed. After the vehicle ispositioned at the dock and the chock is activated to move toward thewheel of the vehicle, both lighting systems will show a red light and anaudible warning can be provided to indicate that the chock is beingmoved. After the chock is secured at the vehicle wheel, the docklighting system will show a green light indicating that loading andunloading operations can be performed, and the driver lighting systemwill remain red, indicating that the vehicle is secured and that thedriver should not attempt to pull away from the dock. After loading andunloading operations are complete, the chock is moved back toward thestored position, during which time both lighting systems will show a redlight and an audible warning will indicate that the chock is beingmoved.

The foregoing description of the present invention has been presentedfor purposes of illustration and description. Furthermore, thedescription is not intended to limit the invention to the form disclosedherein. Consequently, variations and modifications commensurate with theabove teachings, and the skill or knowledge of the relevant art, arewithin the scope of the present invention. The embodiments describedherein are further intended to explain best modes known for practicingthe invention and to enable others skilled in the art to utilize theinvention in such, or other, embodiments and with various modificationsrequired by the particular applications or uses of the presentinvention. It is intended that the appended claims be construed toinclude alternative embodiments to the extent permitted by the priorart.

What is claimed is:
 1. A method of securing a vehicle at a desiredlocation using a wheel chocking device having a chock movable between alowered position and a raised position, said method comprising the stepsof: positioning the vehicle at the desired location with the chock inthe lowered position; raising the chock to the raised position; movingthe raised chock toward a wheel of the vehicle; sensing the presence ofan obstruction on the vehicle; automatically lowering the raised chockto an intermediate position to allow the chock to pass under theobstruction; and contacting the chock with the wheel.
 2. The method ofclaim 1, wherein the chock includes a rear portion for engaging thewheel, and wherein said moving step includes the step of driving therear portion of the chock.
 3. The method of claim 2, wherein the chockfurther includes a front portion movably connected to the rear portion,and wherein said method further comprises the step of moving the chockaway from the wheel by driving the front portion of the chock.
 4. Themethod of claim 1, wherein said sensing step includes the step ofcontacting the chock with the obstruction.
 5. The method of claim 1,further comprising the step of compliantly holding the chock in theraised position such that the chock is vertically deflectable from theraised position to a lower intermediate position.
 6. The method of claim5, wherein the chock includes a rear portion and a front portion, andwherein said holding step includes the step of forcing the front andrear portions together using a biasing member.
 7. The method of claim 1,further comprising the step of securing the chock in the raised positionafter said contacting step.
 8. The method of claim 7, wherein saidsecuring step includes the step of moving a supporting member from anon-supporting position to a supporting position.
 9. A wheel chockingdevice adapted to secure a vehicle in a desired location, said devicecomprising: a chock movable between a lowered position and a raisedposition and drivable to a rearward direction toward a wheel engagingposition and in a frontward direction opposite said rearward direction,said chock including; a rear portion adapted to engage a wheel of thevehicle; and a front portion movably connected to said rear portion,wherein said chock is raised by moving said rear and front portionstoward each other and is lowered by moving said rear and front portionsaway from each other; and a drive mechanism drivingly connected to saidrear portion to move, said entire chock in the rearward direction. 10.The wheel chocking device of claim 9, wherein said drive mechanism isdrivingly connected to said chock such that said drive mechanism drivessaid front portion when moving said chock in the frontward direction.11. The wheel chocking device of claim 9, further comprising acompression spring member operatively positioned between said drivemechanism and said rear portion.
 12. The wheel chocking device of claim11, wherein said compression spring member includes a gas spring. 13.The wheel chocking device of claim 9, further comprising a memberinterconnecting said drive mechanism with said front portion, saidinterconnecting member being adapted to secure the position of saidfront portion when said drive mechanism holds said rear portion inengagement with a vehicle.
 14. The wheel chocking device of claim 13,wherein said interconnecting member includes a rod.
 15. A wheel chockingdevice adapted to secure a vehicle in a desired location, said devicecomprising: a longitudinally extending base frame including side wallsdefining a recess; a chock positioned above said base frame and movablelongitudinally relative to said base frame;, a drive mechanismpositioned within said recess and drivingly connected to said chock; anda cover plate positioned between said base frame and said chock, saidcover plate substantially covering said recess.
 16. The wheel chockingdevice of claim 15, wherein said cover plate includes longitudinallyextending side edges, and wherein said drive mechanism includes a platemember positioned under said cover plate and extending beyond said sideedges of said cover plate.
 17. The wheel chocking device of claim 16,wherein said cover plate moves to allow passage of said plate memberbetween said base frame and said cover plate.
 18. The wheel chockingdevice of claim 15, wherein said cover plate spans substantially theentire longitudinal extent of said base frame.
 19. The wheel chockingdevice of claim 15, wherein said cover plate and base frame are adaptedto support a wheel of a vehicle.
 20. A wheel chocking device adapted tosecure a vehicle in a desired location, said device comprising: a chockmovable between a lowered position and a raised position; and a drivemechanism drivingly connected to said chock so as to drive said chockbetween said lowered and raised positions, said drive mechanismincluding: a screw member mounted for rotation relative to said chockand having an outer circumference; and a drive member having internalthreads that cooperatively engaging said screw member, said drive memberincluding an open portion such that said internal threads do not engagethe entire outer circumference of said screw member.
 21. The wheelchocking device of claim 20, wherein said drive member engages more thanhalf of said outer circumference.
 22. The wheel chocking device of claim20, wherein said screw member includes two ends and an intermediateportion between said two ends, and wherein said device further comprisesa support member positioned to support said intermediate portion of saidscrew member.
 23. The wheel chocking device of claim 22, wherein saidsupport member includes an arcuate recess for supporting said screwmember.
 24. The wheel chocking device of claim 22, wherein said screwmember includes an outer circumference, and wherein said support membersupports half or less of said outer circumference.
 25. The wheelchocking device of claim 22, wherein said support member comprises apolymer material in contact with said screw member.
 26. The wheelchocking device of claim 22, wherein said device includes a plurality ofsaid support members spaced from each other along a length of said screwmember.
 27. A wheel chocking device adapted to secure a vehicle in adesired location, said device comprising: a base frame; a chock movablerelative to said base frame between a lowered position and a raisedposition; and a drive mechanism drivingly connected to said chock so asto drive said chock between said lowered and raised positions, saiddrive mechanism including: a screw member mounted on said base frame forrotation about an axis, said screw member being axially movable relativeto said base frame between a first position and a second position; adrive member having threads that cooperatively engage said screw member;and a sensor for sensing an axial position of said screw member.
 28. Thewheel chocking device of claim 27, wherein said screw member is biasedtoward the first position.
 29. The wheel chocking device of claim 28,wherein said screw member is biased by a spring.
 30. The wheel chockingdevice of claim 27, wherein said screw member is designed to move fromthe first position to the second position when said chock engages avehicle wheel.
 31. The wheel chocking device of claim 27, wherein saidsensor is operatively associated with said drive mechanism such thatsaid drive mechanism is deactivated when said sensor senses that saidscrew member have moved from the first position to the second position.32. A method of securing a vehicle at a desired location using a wheelchocking device having a chock movable between a lowered position and araised position and having a support link moveable relative to the chockbetween a non-supporting position and a supporting position, said methodcomprising the steps of: positioning the vehicle at the desired locationwith the chock in the lowered position and the support link in thenon-supporting position; raising the chock to the raised position whilethe support link stays -in the non-supporting position; and moving thesupport link from the non-supporting position to the supporting positionwhile the chock is in the raised position to thereby support the chockin the raised position.
 33. The method of claim 32, wherein said movingstep includes pivoting the support link.
 34. The method of claim 32,wherein the chock stays in a substantially fully raised position duringsaid moving step.